Question

我已多次尝试读取用户输入，然后将其写入文件但我找不到解决方案。这是我的代码......

主要班级。

import java.util.HashMap;
import java.util.Scanner;

public class cShell{
    static String Currentpath="C:\\";
    public String Current = Currentpath;
    static HashMap<String, ICommand> myhashData=new HashMap<String, ICommand>();

    public static void main(String[] args)
    {
        myhashData.put("ltf", new cITF());
        myhashData.put("nbc", new cNBC());
        myhashData.put("gdb", new cGDB());
        myhashData.put("Tedit", new cTedit());

        String Input = "";
        do{
            System.out.print(Currentpath+"> ");
            //String Input = "";
            Scanner scan = new Scanner(System.in);
            if(scan.hasNext()){
                Input = scan.nextLine().trim();             
            }

            if(Input.equals("exit")){
                System.exit(0);
            }

            if(myhashData.containsKey(Input)){
                ICommand myCommand=myhashData.get(Input);
                myCommand.Execute();
            }
            else{
                System.out.println("Invalid Command");
            }

        }while(!Input.equals("exit"));
    }
}

这是进行读写的类。

import java.util.*;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
//import java.lang.System.*;

public class cTedit implements ICommand{

    @Override
    public void Execute() {         
        String filename = "";
        System.out.println("Enter the file name to be edited");
        Scanner scan = new Scanner(System.in);
        if(scan.hasNext()){
            filename = scan.nextLine();
        }

        String line = null;
        try{
            InputStreamReader ISR = new InputStreamReader(System.in);
            //FileReader fileReader = new FileReader(ISR);
            FileWriter fileWriter = new FileWriter(cShell.Currentpath+"\\"+filename);
            BufferedReader bufferedReader = new BufferedReader(ISR);
            System.out.println("Enter text into the file");
            while((line = bufferedReader.readLine()) != null){
                 fileWriter.write(line);
            }
        bufferedReader.close();
        }catch(FileNotFoundException ex){
            System.out.println("Unable to open file '" + filename + "'");
        }
        catch(IOException ex){
            System.out.println("Error reading file '" + filename + "'");
        }
    }
}

我的问题是当我输入一些文本作为用户输入时，按Enter键不会阻止我输入输入，但是当我按下Ctrl + z时它会进入一个无限循环。

Answer 1

在cTedit课程中试试这个。

bufferedReader.readLine()永远不会在您的案例中返回null。

键入exit以退出循环。

    while((line = bufferedReader.readLine()) != null){
         if(line.equals("exit")){
           break;
         }
         fileWriter.write(line);
     }

最后使用fileWriter.close()。

Answer 2

也许这不是问题的根源，但我认为你不需要检查hasnext（）条件来读取一行：

if(scan.hasNext()){
     filename = scan.nextLine();
}

只需filename = scan.nextLine();即可。

Answer 3

使用以下

 if(Input.equals("exit") || Input.equals("")){
                System.exit(0);
 }

而不是

 if(Input.equals("exit")){
                System.exit(0);
}

要在退出之前关闭fileWriter，请按以下方式添加方法closeFile。

import java.util。; import java.io。; import java.nio.file.Files; import java.nio.file.Path; // import java.lang.System。*;

public class cTedit实现ICommand { private FileWriter fileWriter; @覆盖 public void Execute（）{ // TODO自动生成的方法存根

String filename = "";
System.out.println("Enter the file name to be edited");
Scanner scan = new Scanner(System.in);
if(scan.hasNext()){
    filename = scan.nextLine();
}

String line = null;

try{

    InputStreamReader ISR = new InputStreamReader(System.in);
    //FileReader fileReader = new FileReader(ISR);
    fileWriter = new FileWriter(cShell.Currentpath+"\\"+filename);

      BufferedReader bufferedReader = new BufferedReader(ISR);
    System.out.println("Enter text into the file");
    while((line = bufferedReader.readLine()) != null){
         fileWriter.write(line);
     }
     bufferedReader.close();
}catch(FileNotFoundException ex){
    System.out.println("Unable to open file '" + filename + "'");
}
catch(IOException ex){
    System.out.println("Error reading file '" + filename + "'");
} finally {
    fileWriter.close();
}

}

 public void closeFile() {
     fileWriter.close();
 }

}

在退出

之前，在callCloseFile课程中

然后cShell

无法将输入写入文件

3 个答案: